Inflatable vehicle air-bags are generally formed from one or more sheets of fabric which are sealed together to form a substantially enclosed internal chamber. When the air-bag is activated, pressurised gas is introduced rapidly into the interior to inflate the air-bag, thus providing a cushioning barrier between an occupant of the vehicle, or a pedestrian, and a stiff, structural part of the vehicle.
Fabrics for use in the manufacture of air-bags are generally formed from warp and weft yarns, which are interwoven substantially at right angles to one another. Conventionally, the warp and weft yarns are monofilament or multifilament yarns, and many different types of yarn may be used for this purpose.
In certain circumstances, for instance in the manufacture of a side-impact air-bag, it is desirable to increase the stiffness of the air-bag in order to increase the resistance of the air-bag to the load imposed by an occupant impacting against the air-bag.